Cryogenic microtome apparatus

ABSTRACT

Microtome apparatus with parts specially formed and arranged for cutting thin and ultra thin tissue sections under cryogenic conditions. The microtome is provided with an insulated enclosure or container for the cryogenic fluid and a stationary, but adjustable, cutting knife. The swinging fulcrum arm of the microtome has at its outer end a U-shaped specimen holder so designed to enable the specimen holder assembly to straddle one wall of the container. Thus, the stationary knife edge is horizontally aligned with the fulcrum arm pivot point without need for a sealed container-wall fulcrum arm passageway.



1. Cryogenic equipment for a microtome having a pivoting fulcrum comprising a frame, a container made of insulating material, a microtome knife positioned in said container, an inverted Ushaped specimen holder assembly mounted on the free end of said fulcrum, the spaced legs of said specimen holder assembly straddling a wall of said container and movable reciprocably and freely relative thereto, the outer leg of said specimen holder assembly extending into said container, a tissue holder removably mounted on said outer leg in a position where a tissue specimen mounted on said tissue holder is sectioned by the cutting edge of said knife when said fulcrum moves through one of its reciprocating passes.
 2. Cryogenic equipment according to claim 1 wherein at least a portion of said U-shaped specimen holder assembly comprises a thermal barrier for thermally insulating said fulcrum from the materials in said container.
 3. Cryogenic equipment according to claim 1 wherein said outer leg is made of thermally insulating material.
 4. Cryogenic equipment according to claim 1 wherein said U-shaped specimen holder assembly is removably mounted on said fulcrum.
 5. Cryogenic equipment according to claim 1 wherein said container is removably mounted on said frame.
 6. Cryogenic equipment according to claim 1 and further comprising a lock element for adjustably securing said U-shaped specimen holder assembly in a desired position relative to said fulcrum.
 7. Cryogenic equipment according to claim 1 wherein said tissue holder is removably connected to said outer leg.
 8. Cryogenic equipment according to claim 1 wherein said tissue holder is made of a highly thermally conductive material.
 9. Cryogenic equipment according to claim 8 and further comprising a highly thermally conductive chuck on said outer leG in which said tissue holder is adjustably mounted.
 10. Cryogenic equipment according to claim 1 and further comprising a locking element on said outer leg for securing said tissue holder in position, the position of said tissue holder being adjustable for locating the tissue specimen on said holder in a determined position relative to the knife.
 11. Cryogenic equipment according to claim 1 wherein the pivot point of said fulcrum is in approximately the same plane as the cutting edge of said knife.
 12. A microtome for sectioning biological tissues or the like under cryogenic conditions comprising a frame, a fulcrum mounted pivotally on said frame, a container of insulating material for accommodating a quantity of cryogenic fluid mounted on said frame, a microtome knife positioned in said container, first means on said fulcrum freely bypassing a wall of said container and extending into the interior of said container, and second means mounted on that portion of the first means extending into the interior of said container for supporting a tissue specimen to be sectioned by said knife.
 13. Microtome according to claim 12 wherein the cutting edge of said microtome knife is in substantially the same plane with the pivot point of said fulcrum.
 14. A microtome according to claim 12 wherein said first means moves freely relative to said container wall during the complete oscillating movement of said fulcrum.
 15. A microtome according to claim 12 wherein at least a portion of said first means is made of a thermally insulating material for thermally isolating said fulcrum from said second means.
 16. A microtome according to claim 12 wherein said first means has an inverted U-shaped form.
 17. A microtome according to claim 12 wherein said first means is removably mounted on said fulcrum.
 18. A microtome according to claim 12 wherein said second means comprises a highly thermally conductive metal.
 19. A microtome according to claim 18 wherein said second means is removably mounted on said first means.
 20. A microtome according to claim 12 wherein said container with said microtome therein is removably mounted on said frame.
 21. A microtome for sectioning biological tissues or the like under cryogenic conditions comprising a frame, a fulcrum mounted pivotally on said frame, a container of insulating material for accommodating a quantity of cryogenic liquid mounted on said frame, a microtome knife positioned in said container, the cutting edge of said knife being located in substantially the same horizontal plane as the pivot point of said fulcrum, an inverted U-shaped specimen holder assembly mounted on the free end of said fulcrum and extending freely over and around one wall of said container, the outer leg of said assembly extending into the interior of said container, and a tissue holder mounted on the lower portion of said leg for moving a tissue specimen on said holder relative to the cutting edge of said knife. 